The present invention relates to an ignition device with speed limitation for internal combustion engines in which a trigger pulse actuates a switching or contact mechanism used for generating the ignition high voltage, particularly a capacitor ignition device with thyristor control.
The known speed limiter devices have in common that the voltage induced by a rotating magnet system in a coil, and depending on the rpm of the magnet system, serves as a speed criterion. A significant disadvantage of the method is that the voltage depends not only on the rpm of the magnet system, but also on the air gap width between the rotating magnet system and the fixed core, and on the field strength of the field spider magnet. This makes it nearly impossible for the manufacturer of such ignition systems to predetermine a definite speed limit for the ignition system without expensive individual tests and adjustments of each individual ignition system.
Accordingly, it is an object of the present invention to avoid these difficulties and to provide an ignition device with speed limitation for internal combustion engines where a simple determination by the manufacturer of the speed limits is possible within narrow tolerances.
Another object of the present invention is to provide an ignition device of the foregoing character which is substantially simple in construction and may be economically fabricated.
A further object of the present invention is to provide an ignition device, as described, which may be readily maintained in service and which has a substantially longer operating life.